Mind the gap but also the spin: why the Heyd-Scuseria-Ernzerhof hybrid functional description of VO2 phases is not correct

TL;DR

This paper critically evaluates the HSE hybrid functional's ability to accurately describe VO2 phases, revealing significant discrepancies with experimental data regarding magnetic and electronic properties.

Contribution

It demonstrates that the HSE functional's predictions for VO2 phases are inconsistent with experimental observations, challenging its reliability for this material.

Findings

HSE predicts a magnetic ground state for M1 VO2, contrary to experiments.

HSE suggests R VO2 is spin-polarized and not metallic, conflicting with known properties.

Energy differences between phases do not match experimental latent heat values.

Abstract

In contrast with recent claims that the Heyd-Scuseria-Ernzerhof (HSE) screened hybrid functional can provide a good description of the electronic and magnetic structure of VO2 phases [V. Eyert, Phys. Rev. Lett. 107, 016401 (2011)], we show here that the HSE lowest-energy solutions for both the low-temperature monoclinic (M1) phase and the high-temperature rutile (R) phase, which are obtained upon inclusion of spin polarization, are at odds with experimental observations. For the M1 phase the groundstate is (but should not be) magnetic, while the groundstate of the R phase, which is also spin-polarized, is not (but should be) metallic. The energy difference between the low-temperature and high-temperature phases is also in strong discrepancy with the experimental latent heat.